He is an expert in ichthyology and has a deep knowledge of marine life.

He told me the whole story of the incident.

He explained the structure of the arytenoid cartilage in the throat in detail.

He injured the sesamoid cartilage in his foot.

He is a world-renowned ichthyologist.

His room is full of heaps of books.

I eat fish every Friday.

There are many fish in this river.

I eat fish every Friday.

I eat fish every week.